Autoignition-assisted flame regime of sustainable aviation fuel, ammonia and dimethyl ether blends

该项目旨在研究用于能源应用的新型可持续环保燃料的燃烧行为。此类新燃料将有助于减少能源、交通和工业领域的碳排放。新燃料的关键成分之一是氨（NH3），这是一种氢含量高的燃料。虽然氨可以比氢更安全地储存和运输，但氨的燃烧不同于汽油、柴油和航空燃料等传统化石燃料。因此，该研究项目旨在研究氨和高反应性生物质二甲醚（DME）的组合，以复制传统化石燃料的实际燃烧行为。火焰速度和点火延迟是在燃烧过程中发挥重要作用的两个基本燃料混合物特性。这两个特性因其在设计和开发先进燃烧系统中的重要性而被广泛研究。然而，火焰和自燃同时影响燃烧过程的燃烧状态尚不清楚。这种燃烧方式称为自燃辅助火焰，与传统的层流火焰或扩散火焰相比具有不同的形态和特征。在这种燃烧状态下，火焰在中间物质池上传播，这些中间物质是由于混合物的低温化学作用而产生的。这里的研究目标是了解和量化氨和二甲醚混合物在高温和高压下的自燃辅助预混层流火焰。将通过实验和数值研究不同气体温度、压力、当量比和丹克勒数的火焰状态。快速压缩机火焰 (RCM-FLAME) 装置用于通过多种光学诊断技术研究火焰状态。拟议项目有四个变革性方面：(1) 在广泛的物理化学条件下量化火焰传播速度，(2) 第一阶段和第二阶段自燃对火焰传播速度影响的实验研究，(3) 拉伸对向外传播的球形自燃辅助火焰的影响，以及 (4) 在模拟氨-DME 混合物燃烧时开发的动力学模型的准确性。该奖项反映了 NSF 的法定使命，并被认为是值得的。通过使用基金会的智力优势和更广泛的影响审查标准进行评估来获得支持。

This project aims to study the combustion behavior of a new class of sustainable and environmentally friendly fuels for energy applications. Such new fuels will help reduce carbon emissions in the energy, transportation, and industrial sectors. One of the critical components of the new fuel is ammonia (NH3), a fuel with high hydrogen content. While ammonia can be stored and transported more safely than hydrogen, ammonia combustion differs from traditional fossil fuels like gasoline, diesel, and aviation fuels. Therefore, this research project aims to investigate a combination of ammonia and a highly reactive and biomass derived Dimethyl Ether (DME) to replicate the practical combustion behavior of traditional fossil fuels.Flame speed and ignition delay are two fundamental fuel mixture characteristics that play significant roles in the combustion process. Both characteristics have been studied extensively for their importance in designing and developing advanced combustion systems. However, the combustion regime in which the flame and autoignition simultaneously affect the combustion process is not well understood. This combustion regime is called autoignition-assisted flame and has a different morphology and characteristics with respect to traditional laminar premised or diffusion flames. In this combustion regime, the flame propagates over a pool of intermediate species, which are produced due to the low-temperature chemistry of the mixture. The research objective here is to understand and quantify the autoignition-assisted premixed laminar flame of ammonia and DME blends at elevated gas temperatures and pressures. The flame regimes across various gas temperatures, pressures, equivalence ratios, and Damkӧhler numbers will be investigated experimentally and numerically. The Rapid Compression Machine–Flame (RCM-FLAME) apparatus is used to study the flame regime with several optical diagnostic techniques. The proposed project has four transformative aspects: (1) quantification of flame propagation speed over a wide range of physico-chemical conditions, (2) experimental investigation of the effects of first-stage and second-stage autoignition on flame propagation speed, (3) the effect of stretch on outwardly propagating spherical autoignition-assisted flames, and (4) accuracy of kinetic models developed in simulating the combustion of ammonia-DME mixtures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.